CASIMIRO DE ABREU, Brazil – This small city in the state of Rio de Janeiro is on high alert after authorities confirmed the death of one man by yellow fever and are investigating several other possible cases.

Health authorities this week confirmed that 38-year-old Watila Santos died from the illness on March 11.

Authorities are investigating possible cases involving four relatives of Santos, including a 13-year-old and a 9-year-old.